#pragma once
#include "memory.h"
namespace MD5
{
	#define S11 7
	#define S12 12
	#define S13 17
	#define S14 22
	#define S21 5
	#define S22 9
	#define S23 14
	#define S24 20
	#define S31 4
	#define S32 11
	#define S33 16
	#define S34 23
	#define S41 6
	#define S42 10
	#define S43 15
	#define S44 21
	typedef unsigned long int UINT32;
	typedef unsigned short int UINT16;

	/* MD5 context. */
	typedef struct {
		UINT32 state[4];                                   /* state (ABCD) */
		UINT32 count[2];        /* number of bits, modulo 2^64 (lsb first) */
		unsigned char buffer[64];                         /* input buffer */
	} MD5_CTX;

	void MD5Init(MD5_CTX *);
	void MD5Update(MD5_CTX *, unsigned char *, unsigned int);
	void MD5Final(unsigned char[16], MD5_CTX *);


	static void MD5Transform(UINT32 a[4], unsigned char b[64]);
	static void Encode(unsigned char *, UINT32 *, unsigned int);
	static void Decode(UINT32 *, unsigned char *, unsigned int);

	static unsigned char PADDING[64] = {
		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	};

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (UINT32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (UINT32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
		}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (UINT32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
		}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (UINT32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
		}

	void MD5Init(MD5_CTX *context)
	{
		context->count[0] = context->count[1] = 0;

		context->state[0] = 0x67452301;
		context->state[1] = 0xefcdab89;
		context->state[2] = 0x98badcfe;
		context->state[3] = 0x10325476;
	}

	void MD5Update(MD5_CTX *context, unsigned char *input, unsigned int inputLen)
	{
		unsigned int i, index, partLen;

		index = (unsigned int)((context->count[0] >> 3) & 0x3F);

		if ((context->count[0] += ((UINT32)inputLen << 3))
			< ((UINT32)inputLen << 3))
			context->count[1]++;
		context->count[1] += ((UINT32)inputLen >> 29);

		partLen = 64 - index;

		if (inputLen >= partLen) {
			memcpy((unsigned char *)&context->buffer[index], (unsigned char *)input, partLen);
			MD5Transform(context->state, context->buffer);

			for (i = partLen; i + 63 < inputLen; i += 64)
				MD5Transform(context->state, &input[i]);

			index = 0;
		}
		else
			i = 0;

		memcpy((unsigned char *)&context->buffer[index], (unsigned char *)&input[i],
			inputLen - i);
	}

	void MD5Final(unsigned char digest[16], MD5_CTX * context)
	{
		unsigned char bits[8];
		unsigned int index, padLen;

		Encode(bits, context->count, 8);

		index = (unsigned int)((context->count[0] >> 3) & 0x3f);
		padLen = (index < 56) ? (56 - index) : (120 - index);
		MD5Update(context, PADDING, padLen);

		MD5Update(context, bits, 8);

		Encode(digest, context->state, 16);

		memset((unsigned char *)context, 0, sizeof (*context));
	}

	static void MD5Transform(UINT32 state[4], unsigned char block[64])
	{
		UINT32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

		Decode(x, block, 64);

		/* Round 1 */
		FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
		FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
		FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
		FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
		FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
		FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
		FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
		FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
		FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
		FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
		FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
		FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
		FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
		FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
		FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
		FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

		/* Round 2 */
		GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
		GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
		GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
		GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
		GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
		GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
		GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
		GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
		GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
		GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
		GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
		GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
		GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
		GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
		GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
		GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

		/* Round 3 */
		HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
		HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
		HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
		HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
		HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
		HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
		HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
		HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
		HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
		HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
		HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
		HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
		HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
		HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
		HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
		HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */

		/* Round 4 */
		II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
		II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
		II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
		II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
		II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
		II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
		II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
		II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
		II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
		II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
		II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
		II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
		II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
		II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
		II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
		II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */

		state[0] += a;
		state[1] += b;
		state[2] += c;
		state[3] += d;

		memset((unsigned char *)x, 0, sizeof (x));
	}

	static void Encode(unsigned char *output, UINT32 *input, unsigned int len)
	{
		unsigned int i, j;

		for (i = 0, j = 0; j < len; i++, j += 4) {
			output[j] = (unsigned char)(input[i] & 0xff);
			output[j + 1] = (unsigned char)((input[i] >> 8) & 0xff);
			output[j + 2] = (unsigned char)((input[i] >> 16) & 0xff);
			output[j + 3] = (unsigned char)((input[i] >> 24) & 0xff);
		}
	}

	static void Decode(UINT32 *output, unsigned char *input, unsigned int len)
	{
		unsigned int i, j;

		for (i = 0, j = 0; j < len; i++, j += 4)
			output[i] = ((UINT32)input[j]) | (((UINT32)input[j + 1]) << 8) |
			(((UINT32)input[j + 2]) << 16) | (((UINT32)input[j + 3]) << 24);
	}
}
